高空大气运动的分布特征及其对LOD的贡献

THE DISTRIBUTION OF ATMOSPHERIC CIRCULATION IN THE STRATOSPHERE AND LOWER MESOSPHERE AND ITS CONTRIBUTION TO LOD

根据世界资料中心（ＷＤＣ）Ａ提供的地球２０－６０ｋｍ高度的大气运动资料，分析研究了高空大气运动的分布特征．结果表明，不同纬度带和不同高度的大气相对运动角动量、大气摩擦力矩均具有周年分布特征，位相分布与近地大气环流特征相一致．大气运动的垂直变化与季节有关．用角动量法定量估计了高空大气环流对地球自转日长（ＬＯＤ）变化的贡献，证实高空大气运动对地球自转的作用是值得考虑的．

By using the data obtaind from the wind measurements from 1964 to 1969 reported by four stations of the U、S.Meteorological Radar Network, the distributive features of atmospheric circulation over 20 km have been analysed. The primary results obatined show that:1.At:Atmospheric angular momentum in different latitude belts and different height belts show obviously the annual distribution,and have the coincident phase changes with that of the atmospheric angular momentum below 20 km.2.Atmospheric viscous torques'in the different belts mentioned above also have the annual distributive features.3.Augular momentum density profiles and energy density profiles of wind speed very with the height, show that axial Wind component between the heights of 20-40 km in the±(0°-40°)latitude belt is of more relative importance on the changes Of LOD than that in the latitude belt of ±(40°-70°). 4.The annual amplitude of the change of LOD caused by atmospheric angular momentun in the latitued belt of ±(0°-70°) is about 0. 24 ms, which probably explicated the diffrence between the observed annual change of LOD and the calculated value with the data of atmospheric angular momentum below 20 km.